Rhamnetin: a review of its pharmacology and toxicity.

OBJECTIVES: Numerous natural products, including rhamnetin, have been studied in recent years owing to the need for new herbal remedies to treat different illnesses. This study aimed to review the salient properties of rhamnetin and its pharmacological potential and possible toxicological effects. KEY FINDINGS: A search carried out in the ScienceDirect database using the term 'rhamnetin' yielded 573 articles published between 1977 and 2021. However, only those studies that mentioned pharmacological activity of rhamnetin were included in this study. As a result of this selection process, this study included reports that describe rhamnetin as a secondary metabolite with several pharmacological properties. SUMMARY: Rhamnetin (2-(3,4-dihydroxyphenyl)-3,5-dihydroxy-7-methoxychromen-4-one) is a secondary metabolite, belonging to the flavonoid class, present in various plants and fruits; it has different pharmacological properties, including antioxidant, anticancer, anti-inflammatory, antiviral and antibacterial activity. However, conclusive results on the toxicology of rhamnetin have not been reported yet. Therefore, further research is needed to gather detailed information about the effects of rhamnetin.

The benefits of using selenium in the treatment of Chagas disease: prevention of right ventricle chamber dilatation and reversion of Trypanosoma cruzi-induced acute and chronic cardiomyopathy in mice.

Cardiac damage is a frequent manifestation of Chagas disease, which is caused by the parasite Trypanosoma cruzi. Selenium (Se) is an essential micronutrient, the deficiency of which has been implicated in the development of cardiomyopathy. Our group has previously demonstrated that Se supplementation prevents myocardial damage during acute T. cruzi infection in mice. In this study, we analyzed the effect of Se treatment in cases of T. cruzi infection using prevention and reversion schemes. In the Se prevention scheme, mice were given Se supplements (2 ppm) starting two weeks prior to inoculation with T. cruzi(Brazil strain) and continuing until 120 days post-infection (dpi). In the Se reversion scheme, mice were treated with Se (4 ppm) for 100 days, starting at 160 dpi. Dilatation of the right ventricle was observed in the infected control group at both phases of T. cruzi infection, but it was not observed in the infected group that received Se treatment. Surviving infected mice that were submitted to the Se reversion scheme presented normal P wave values and reduced inflammation of the pericardium. These data indicate that Se treatment prevents right ventricular chamber increase and thus can be proposed as an adjuvant therapy for cardiac alterations already established by T. cruzi infection.

The benefits of using selenium in the treatment of Chagas disease: prevention of right ventricle chamber dilatation and reversion of Trypanosoma cruzi-induced acute and chronic cardiomyopathy in mice

Cardiac damage is a frequent manifestation of Chagas disease, which is caused by the parasite Trypanosoma cruzi. Selenium (Se) is an essential micronutrient, the deficiency of which has been implicated in the development of cardiomyopathy. Our group has previously demonstrated that Se supplementation prevents myocardial damage during acute T. cruzi infection in mice. In this study, we analyzed the effect of Se treatment in cases of T. cruzi infection using prevention and reversion schemes. In the Se prevention scheme, mice were given Se supplements (2 ppm) starting two weeks prior to inoculation with T. cruzi(Brazil strain) and continuing until 120 days post-infection (dpi). In the Se reversion scheme, mice were treated with Se (4 ppm) for 100 days, starting at 160 dpi. Dilatation of the right ventricle was observed in the infected control group at both phases of T. cruzi infection, but it was not observed in the infected group that received Se treatment. Surviving infected mice that were submitted to the Se reversion scheme presented normal P wave values and reduced inflammation of the pericardium. These data indicate that Se treatment prevents right ventricular chamber increase and thus can be proposed as an adjuvant therapy for cardiac alterations already established by T. cruziinfection.

Trypanosoma cruzi infection: do distinct populations cause intestinal motility alteration?

Chagas disease, caused by Trypanosoma cruzi, is an important public health problem in Latin America. Disturbances in gastrointestinal motility are observed in 15-20% of patients at the chronic phase. We previously observed a decrease in intestinal motility in mice infected with Y strain from T. cruzi. Thus, we decided to test if infection with other T. cruzi strains also caused the intestinal disturbance. Male adult Swiss mice were infected intraperitoneally with CL-Brener clone (CL-B), Brazil strain (Br), or Dm28 clone (Dm) of T. cruzi. All infected mice presented a low cumulative mortality (CL-B, 17%; Br, 8%; Dm, 25%) at 35 days post infection (dpi) and their typical parasitemia curves. Br and Dm groups exhibited a maximal reduction of intestinal motility at 35 dpi (176.8 +/- 51.3 and 198.3 +/- 52.6 min, respectively), when compared with non-infected mice (90.2 +/- 19.5 min). However, CL mice presented the peak of delayed intestinal transit at 12 dpi (191.0 +/- 33.3 min), when compared with non-infected mice (105.6 +/- 26.4 min), very close to the 15 dpi for the intense alteration (310.2 +/- 67.4 min) observed with the Y strain. We clearly demonstrate a reduction in intestinal motility in mice infected with different groups of T. cruzi during the acute phase of the infection. Since Br, Dm, and CL strains presented low mortality rates in adult Swiss mice, a prospective study concerning the chronic intestinal alteration is encouraged, particularly for studies of alternative therapies.

Applicability of the use of charcoal for the evaluation of intestinal motility in a murine model of Trypanosoma cruzi infection.

Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a serious public health problem in Latin America. In relation to digestive problems, 4.5% of patients show mega syndromes (megacolon) in the chronic phase. In this article, we evaluated intestinal motility at the acute phase of T. cruzi infection through charcoal ingestion in adult mice. After infection, Swiss mice were administered an aqueous suspension of charcoal in water by gavage. Decrease in intestinal motility was determined by increased time of appearance of charcoal in the feces. The uninfected group showed a mean time of charcoal elimination of 109.0 +/- 14.6 min throughout the assay. On the other hand, infected mice presented a significant increase in charcoal defecation time during infection. At 15 days postinfection, infected mice showed a significant increase in charcoal defecation time, 310.2 +/- 67.4 min when compared to the uninfected group, which presented 97.8 +/- 31.8 min, indicating that the T. cruzi infection interferes with intestinal motility. Our results demonstrate that the use of charcoal is an ethical and efficient procedure to evaluate the intestinal motility in the murine model of T. cruzi infection.

Toll-like receptor 4 (TLR4)-dependent proinflammatory and immunomodulatory properties of the glycoinositolphospholipid (GIPL) from Trypanosoma cruzi.

We have demonstrated recently that the glycoinositolphospholipid (GIPL) molecule from the protozoan Trypanosoma cruzi is a TLR4 agonist with proinflammatory effects. Here, we show that GIPL-induced neutrophil recruitment into the peritoneal cavity is mediated by at least two pathways: one, where IL-1beta acts downstream of TNF-alpha, and a second, which is IL-1beta- and TNFRI-independent. Moreover, NKT cells participate in this proinflammatory cascade, as in GIPL-treated CD1d(-/-) mice, TNF-alpha and MIP-2 levels are reduced significantly. As a consequence of this inflammatory response, spleen and lymph nodes of GIPL-treated mice have an increase in the percentage of T and B cells expressing the CD69 activation marker. Cell-transfer experiments demonstrate that T and B cell activation by GIPL is an indirect effect, which relies on the expression of TLR4 by other cell types. Moreover, although signaling through TNFRI contributes to the activation of B and gammadelta+ T cells, it is not required for increasing CD69 expression on alphabeta+ T lymphocytes. It is interesting that T cells are also functionally affected by GIPL treatment, as spleen cells from GIPL-injected mice show enhanced production of IL-4 following in vitro stimulation by anti-CD3. Together, these results contribute to the understanding of the inflammatory properties of the GIPL molecule, pointing to its potential role as a parasite-derived modulator of the immune response during T. cruzi infection.

Avaliação da percepção da fala de crianças deficientes auditivas não-oralizadas pela análise de vídeos / Evaluation of speech perception of pre-verbal hearing impaired children through videotape analysis

Tema: avaliação da percepção da fala de crianças deficientes auditivas pré-verbais. Objetivo: apresentar o método de avaliação de vídeo da interação entre crianças deficientes auditivas pré-verbais e seus pais (Cole et al., 1984), e as adaptações realizadas para avaliação da percepção da fala (Medeiros,2000). O método será apresentado em sua forma original e as adaptações pertinentes. Conclusão: o método possibilita a avaliação da percepção da fala da criança deficiente auditiva, o papel da audição na produção e reformulação da fala e a avaliação do comportamento da mãe diante das respostas auditivas do filho.